1. Filed of the Invention
The present invention concerns a seal structure for fuel cell separators, has the purpose of preventing fuel gas from leaking and would be used especially in the case of integration of the seal body in the separator.
2. Description of the Related Art
With a view to reduction of the number of manufacturing steps and cost, constitution of the cell of a fuel cell by integrating beforehand a seal rubber for preventing leakage of fuel gas in separators and sandwiching an electrolyte membrane 103 with two separators 101, 102 as shown in FIG. 5 has been conceived.
FIG. 6 shows two separators 101, 102 and the electrolyte membrane 103 composing a single cell, and both separators 101, 102 are shown on their side opposed to the electrolyte membrane 103 with integrally provided seal rubbers 104, 105.
In FIG. 6, the continuous seal rubber 104 sealing an area surrounding an electrode 106, passage grooves 107, 108 and manifolds 109, 110, and sealing independently holes 111, 112 is integrated with the separator 101. On the other hand, the continuous seal rubber 105 sealing an area surrounding an electrode 113, passage grooves 114, 115 and manifolds 115, 117 and sealing independently holes 118, 119 is integrated with the separator 102.
The cell for the fuel cell is composed by sandwiching the electrolyte membrane 103 of a size larger than the illustrated electrodes 106, 113 between these seal rubbers 104, 105 integrated respectively with two separators 101, 102, and arranging the faces of the separators 101, 102 integrated with the seal rubbers 104, 105 face to face with each other.
Here, as shown in FIG. 7 illustrating a cross section view of FIG. 6 B-B, where the electrolyte membrane 103 is sandwiched between the separators 101, 102, the sealing is realized by bringing a spacer 120 and the seal rubber 105 into contact with the electrolyte membrane 103, and by arranging the spacer 120 across the passage groove 107, which allows compression of the seal rubber 105 by the spacer 120 because there is no seal rubber 104 for the passage groove 107 portion connecting the electrode 106 and the manifold 109.
However, the spacer 120 cannot be arranged continuously with the seal rubber 104, a certain gap S is inevitably formed between the spacer 120 and the seal rubber 104. The presence of this gap S, as shown in FIG. 8, allows the electrolyte membrane 103 to enter the space S, and the seal rubber 105 and the electrolyte membrane 103 were separated from each other, so that sealing is not established, resulting in leakage of fuel gas.